I will close up under some circumstances, but only if it can be done preemptively enough that it is not dangerous. I normally only do this if in a heavy traffic situation moving slowly where the intruder really is not gaining much but is stealing my comfortable following distance.

If they want to pass me and move on I have no issues with it. it does irritate if they pass then slow down once in front.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.